The voice of Laith al-Hemary's brother whispered on the mobile phone: "There are shouts and screams coming from outside. They are killing everyone they find."

Then the line went dead.

It was the last time Mr Hemary (30) spoke to his brother before he was killed inside his home in the Syrian hamlet of Qubair on Wednesday.

He was among 78 victims who are believed to have died in a frenzied onslaught in this village in a farming district some 15 miles from the city of Hama.

The full horror of the atrocity was betrayed by bloody videos of mutilated children's bodies and charred corpses.

In a few hours, almost the entire population of Qubair was massacred in what appears to have been one of the bloodiest incidents since the start of the Syrian uprising.

Forces loyal to President Bashar al-Assad were responsible, according to opposition activists. They said that regular forces were working in tandem with a pro-government militia, known as the Shabiha, recruited largely from Mr Assad's minority Alawite sect.

The regime's troops began the attack on Wednesday afternoon with a heavy artillery barrage, said the activists. Then Shabiha militiamen entered the hamlet armed with sticks, guns and knives. They attacked homes and farmhouses, shooting and slaughtering all the inhabitants they could find.

Mr Hemary and his cousin were among only a handful of survivors of the massacre.

"I could see thick smoke rising from Qubair," he said. "I called my brother constantly on the mobile. He was hiding in our home. He told me cars full of Shabiha had come to the village and were attacking everyone and burning houses."

At 5.10pm, three hours after the attack began, Mr Hemary's brother's voice died away and he stopped answering his calls. Pushing open the door of his home several hours later, Mr Hemary found the bloodied bodies of his mother, three sisters and three brothers on the ground.

Beaten

"They had been beaten on the head by sticks and stabbed with knives," he said. "I went to other homes. I saw family after family slaughtered by knives." After the militia departed and Qubeir fell quiet later that evening, people from nearby villages ventured into the stricken hamlet.

"I saw a two-month-old child without a head," said Abou Hisham al-Hamouli, who lives in a village close by.

"I saw the burnt corpse of a woman. Her two children were wrapped around, hugging her. They died like that. There were too many burnt bodies." Other witnesses reported that the militiamen sang songs in praise of Mr Assad.

A former soldier who joined the rebel Free Syrian Army said: "I went into houses and saw children without a head, and others without arms. Some were burned and some were without eyes," he said. There were only five known survivors, he added. The exact number of victims could not be confirmed, but people in nearby villages said they had buried 57 corpses. A further 30 bodies were missing and others had not yet been buried, said activists.